fix(ble): wrapped specify scan channel vs cmd

(cherry picked from commit 33febd990c49ef569ec05490436c7a0950631a86)

Co-authored-by: Zhou Xiao <zhouxiao@espressif.com>

components/bt/controller/esp32c2/ble.c

@@ -35,9 +35,8 @@ void ble_stack_enableVsCmds(bool en)
 
 #if DEFAULT_BT_LE_ROLE_OBSERVER
     scan_stack_enableAdvFlowCtrlVsCmd(en);
-#endif // DEFAULT_BT_LE_ROLE_OBSERVER
-
     scan_stack_enableSpecifyScanChanVsCmd(en);
+#endif // DEFAULT_BT_LE_ROLE_OBSERVER
 
     chanSel_stack_enableSetCsaVsCmd(en);
     hci_stack_enableSetVsEvtMaskVsCmd(en);